<div>
  <input type="text" (keydown)="onKeyDown($event)">
</div>

<ng-container *ngFor="let item of users; let index = index">
  <app-opt #opt [item]="item" class="item">
    {{item.name}}
  </app-opt>
</ng-container>

<app-items [item]="currItem"></app-items>
<button (click)="currItem.name='123123'">Click</button>